BIOLOGICAL DATA AND HABITAT REQUIREMENTS

WILDLIFE SPECIES: Anas crecca
TIMING OF MAJOR LIFE HISTORY EVENTS :
Nesting - Nesting chronology varies geographically. In North Dakota,
green-winged teal generally begin nesting in late April. In the
Northwest Territories, Canada, green-winged teal begin nesting between
late May and early July. At Minto Lakes, Alaska, green-winged teal
initiate nesting as early as June 1 and as late as July 20 [1].
Clutch/incubation - Green-winged teal lay 5 to 16 eggs. The incubation
period is 21 to 23 days [1,14].
Age at sexual maturity - Green-winged teal become sexually mature their
first winter [1].
Fledging - Green-winged teals often fledge 34 to 35 days after hatching
or usually before 6 weeks of age [1,9]. Young green-winged teal have
the fastest growth rate of all ducks [1].
Molting - Male green-winged teal leave females at the start of
incubation and congregate on safe waters to molt. Some populations
undergo an extensive molt migration while others remain on or near
breeding grounds. Females molt on breeding grounds [12].
Migration - Green-winged teal are among the earliest spring migrants.
They arrive on nesting areas almost as soon as the snow melts [9]. In
early February, green-winged teal begin to depart their winter grounds,
and continue through April. In central regions green-winged teal begin
to arrive early in March with peak numbers in early April [1].
In northern areas of the United States, green-winged teal migrating to
wintering grounds appear in early September through mid-December. They
begin migrating into most central regions during September and often
remain through December. On their more southerly winter areas,
green-winged teal arrive as early as late September, but most do not
appear until late November [1].
PREFERRED HABITAT :
Breeding/nesting habitat - Green-winged teal inhabit inland lakes,
marshes, ponds, pools, and shallow streams with dense emergent and
aquatic vegetation [1,4,9,14]. They prefer shallow waters and small
ponds and pools during the breeding season [12]. Green-winged teal are
often found resting on mudbanks or stumps, or perching on low limbs of
dead trees [4]. These ducks nest in depressions on dry ground located
at the base of shrubs, under a log, or in dense grass. The nests are
usually 2 to 300 feet (6-91 m) from water [4]. Green-winged teal avoid
treeless or brushless habitats [9].
Winter habitat - Green-winged teal winter in both freshwater or brackish
marshes, ponds, streams, and estuaries [4,9].
COVER REQUIREMENTS :
Green-winged teal nests are usually concealed both from the side and
from above in heavy grass, weeds, or brushy cover [9]. Cattails,
bulrushes, smartweeds (Polygonum spp.), and other emergent vegetation
provide hiding cover for ducks on water [3].
FOOD HABITS :
Green-winged teal, more than any other species of duck, prefer to seek
food on mud flats. Where mud flats are lacking, they prefer shallow
marshes or temporarily flooded agricultural lands [1,4]. They usually
eat vegetative matter consisting of seeds, stems, and leaves of aquatic
and emergent vegetation. Green-winged teal appear to prefer the small
seeds of nutgrasses (Cyperus spp.), millets (Panicum spp.), and sedges
to larger seeds, but they also consume corn, wheat, barley, and
buttonbush (Cephalanthus spp.) seeds [1]. In marshes, sloughs, and
ponds, green-winged teal select the seeds of bulrushes, pondweeds, and
spikerushes (Eleocharis spp.). To a lesser extent they feed upon the
vegetative parts of muskgrass (Chara spp.), pondweeds, widgeongrass
(Ruppia maritima), and duckweeds (Lemna spp.) [1]. They will
occasionally eat insects, mollusks, and crustaceans [1,4]. Occasionally
during spring months, green-winged teal will gorge on maggots of
decaying fish which are found around ponds [14].
PREDATORS :
Common predators of green-winged teal include humans, skunks (Mephitis
and Spilogale spp.), red foxes (Vulpes vulpes), raccoons (Pryon lotor),
crows (Corvus spp.), and magpies (Pica spp.) [1,6].
MANAGEMENT CONSIDERATIONS :
A large proportion of green-winged teal breed north of the agricultural
lands of Canada. Because so many breed in the wetlands of boreal forest
associations, populations of this species have not declined due to
habitat loss as much as other waterfowl species more confined to the
prairies of Canada [1].
REFERENCES :
NO-ENTRY

FIRE EFFECTS AND USE

WILDLIFE SPECIES: Anas crecca
DIRECT FIRE EFFECTS ON ANIMALS :
Fire during the nesting season can destroy green-winged teal nests [6].
However, green-winged teal hens may continue to nest after fire.
Fritzell [6] reported that after a spring fire in 1970, a green-winged
teal removed one charred egg from a burned nest and laid four additional
eggs. Ducklings and molting adults are especially vulnerable to fire.
Adult nonmolting green-winged teal can probably easily escape fire.
HABITAT RELATED FIRE EFFECTS :
Green-winged teal nesting cover can be removed by fire [6,13]. After
spring burning and mowing at Souris National Wildlife Refuge, North
Dakota, there were 13 percent fewer nesting pairs of seven dabbling duck
species (green-winged teal included) along mowed and burned areas than
where cover was untouched [13]. However, forested uplands adjacent to
aquatic habitats can be converted to grasses and sedges by fire,
increasing the nesting potential of green-winged teal [17]. Large-scale
autumn burning may have a detrimental effect upon marshes by decreasing
their ability to catch and retain drifting snow which adds heavily to
spring run-off. The ability of marsh vegetation to catch and hold snow
can be vital to marsh survival [18]. Fire often removes excessive
accumulations of fast-growing hydrophytes, permitting better waterfowl
access and growth of more desirable duck foods [17].
FIRE USE :
Fire can be used to remove fast-growing, undesirable species such as
common reed (Phragmites australis) and increase desirable green-winged
teal foods such as pondweed and duckweed [15]. The best way to reduce
common reed with prescribed burning is to burn during early summer when
carbohydrate reserves in the plant are low and the soil is dry [8].
Controlled burning can be used to create nesting edge for ducks.
Removal of dense vegetation and woody encroachment is vital if prairie
marshes are to remain in this successional state [18]. According to
Ward [18], spring burning in marshlands is primarily done to remove
vegetation and create more nesting edge. Summer fires are used to
create more permanent changes in the plant community. Fire can also be
used to reduce predator activity through the elimination of hiding cover
[6].
If prescribed burning is used as a management technique, burning must be
completed well before or after the nesting season [18]. Land managers
who burn during the nesting season should consider partial burns.
Partial burns probably have less impact on total vegetation changes and
would result in higher recruitment of waterfowl than complete burns
would [19].
REFERENCES :
NO-ENTRY